Facts on Electroplating & Anodizing: Basics, Specifications and Links

Electroplating: Electroplating, also known as Metal Plating, is the method of applying a metallic coating to another material. This is done by putting a negative charge onto the object to be plated and immersing it into a solution which contains a salt of the metal to be deposited. The metallic ions of the salt carry a positive charge and are attracted to the part. When they reach it, the negatively charged part provides the electrons to "reduce" the positively charged ions to metallic form and create the plating.

Plating can be used for different reasons and the process provides a hard shell for whatever it is plated on. Most items are plated to avoid corrosion or abrasion resistance, while other items are plated for a cosmetic finish.

Aluminum Anodizing: Anodizing is an electrolytic process for producing controlled aluminum oxide films on aluminum. The anodizing process produces a coating which is uniform, much harder, and denser than natural oxidation. It is formed by converting the surface of the part both with a penetration and a build-up of aluminum oxide. Unlike paint, which can flake off if not applied properly, anodized finishes are actually formed from the original material and cannot flake off. The aluminum oxide finish is very hard and exceptionally wear resistant. The aluminum can also be dyed at the end of the anodizing process to get a colored finish.

Electroless Nickel: Electroless nickel (EN) plating is a process that utilizes an autocatalytic chemical reaction instead of electricity to deposit nickel ions onto a part. This type of plating process gives uniform thickness all over the part’s shape and size without the variances that occur in electrolytic plating. This offers a distinct advantage for parts that require very exact tolerances and also offers superior corrosion resistance to electroplated nickel or hard chrome.

RoHS Compliance: Prime Plating can perform RoHS compliant plating processes. We have tested many products as well as our own proprietary solutions for compliance as well as effectiveness. We are more than happy to share our findings with you or your customer on what’s available and how to meet the regulations with a high-quality result.

For anyone not familiar, The RoHS Directive stands for "the Restriction of the use of certain Hazardous Substances in electrical and electronic equipment". This Directive will ban the placing on the EU market of new electrical and electronic equipment containing more than agreed levels of lead, cadmium, mercury, hexavalent chromium, polybrominated biphenyl (PBB) and polybrominated diphenyl ether (PBDE) flame retardants from 1 July 2006

Plating Specifications:

Anodizing	MIL-A-8625
	Type II- Sulfuric Anodize
	Class I- Non Dyed, Class II- Dyed
Cadmium	QQ-P-416 or ASTM-A165
	Class I- 0.0005, Class II- 0.0003, Class III- 0.0002
	Type I- As plated w/o supplementary treatment
	Type II- with supplementary chromate treatment
	Type III-(Conductive) with supplementary phosphate treatment
Cadmium, Low Embrittlement	MIL-STD-870
Chemical Finish: Black	MIL-F-495
Chromate Conversion (Chem Film)MIL-C-5541 or MIL-C-81706	Type IA- heavier coating 40 to 10 mg/square foot Type 3- lighter coating 10 mg/square foot
Copper	MIL-C-14550
	Class 0- 0.001-0.005 for heat treatment stop-off
	Class I- 0.001 carburizing shield
	Class II- 0.0005 plating undercoat
	Class III- 0.0002 prevents metal migration
	Class IV- 0.0001
Electroless Nickel	MIL-C-26074
	Class I- As plated w/o supplementary heat treatment
	Class II- Heat treated to obtain required hardness
	Class III- Aluminum alloys, non-heat-treat
	Class IV- Aluminum alloys, heat-treat
	Grade A- 0.0010
	Grade B- 0.0005
	Grade C- 0.0015
	Commercial- As specified
Gold	ASTM B488 or AMS 2422
Hard Anodize	MIL-A-8625
	Type III- thickness as specified, nominal 0.002
	Class I- Non-dyed
	Class II- Dyed as specified
Nickel	QQ-N-290
	Class I- for corrosion protection
	Class II- for engineering applications
	Grade A- 0.0016
	Grade B- 0.0012
	Grade C- 0.0010
	Grade D- 0.0008
	Grade E- 0.0006
	Grade F- 0.0004
	Grade G- 0.0002
Palladium	MIL-P-45209B or ASTM-B679
Passivate	QQ-P-35
	Type II- medium temperature nitric acid with
	Sodium dichromate
	Type VI- low temperature Citric acid
Phosphate: Heavy	DOD-16232
	Type M- Manganese Phosphate
Phosphate: Light	TT-C-490
	Type I- Zinc Phosphate
	Type II- Iron Phosphate
Rhodium	MIL-R-46085B or ASTM-B634
Silver	QQ-S-365
	Type I- Matte finish
	Type II- Semi-Bright finish
	Grade A- Chromate post-treatment
	Grade B- no supplementary treatment
Sulfamate Nickel	MIL-P-27418
Tin Plating	MIL-T-10727
	Type I- Electrodeposited, 0.0001-0.00025 flash for solder, or 0.0003 min corrosion protection
Zinc	ASTM-B633 or QQ-Z-325
	Service Condition IV or Class I- 0.0010 min
	Service Condition III or Class II- 0.0005 min
	Service Condition II- 0.0003 min
	Service Condition I or Class III- 0.0002
	Type I- As plated w/o supplementary treatment
	Type II- With colored chromate conversion coating
	Type III- With clear chromate conversion coating

Metal Finishing Links:

National Association of Metal Finishers
Metal Finishing Association of Southern California
Products Finishing
Kushner Electroplating School